Reduction of metals from their ores, &amp;c., in electrically-heated furnaces.



No. 705,651. Patented July 29, I902.

R: G. CUNTARDO.

REDUCTION OF METALS FROM THEIR ORES, &c., IN ELECTRICALLY HEATEDFURNACES.

(Application filed Dec. 1, 1897.)

(lo Model.) 3 Sheets-Sheet l.

11201612133565 lave/122W fm 25W Rls vETsws m. PHOYG mwo. WASHINGTQN. qc.

No. 7 05,65l. Patented July 29, 1902.

R. c. CONTARDO. REDUCTION OF METALS FROM THEIR ORES, &c., INELEGTRIGALLY HEATED FURNACES.

(Application filed Dec. 1, 1897.)

WM m a! w k m 4 4; H 5 J W x. 1 +m a WW M ,W/ H. l a I6 T J M m w a m mw w N0. 705,65I. Patented July 29, I902.

R. C. CONTARDD.

REDUCTION OF METALS FROM THEIR (IRES, &I:., IN ELECTRIC'ALLY HEATEDFURNACES.

(Application filed Dec. 1, 1897.}

(No Nodal.) 3 Sheets-Sheet 3.

ZlJLnessc-zs y .[720676202' UNITED STATES E PATENT- OFFICE.

RAMON OHAVARRIA CONTARDO, OF SlCVRES, FRANCE.

REDUCTION OF METALS FROM THEIR ORES, do, lN ELECTRlCALLY-HEATEDFURNACES.

SPECIFICATION forming part of Letters Patent No. 705,651, dated July 29,1902.

Application filed December 1, 1897.

T0 ctZZ whom it may concern:

Be it known that I, RAMON CHAVARRIA OONTARDO, doctor of laws, a citizenof the Re public of Chile, and a resident of Santiago, Chile, but atpresent residing atNo. 5 Rue de la Plaine Perdue, Sevres, in thedepartment of Seine, France, have invented new and useful Improvementsin the Reduction of Metals from Their Ores and the Like and inElectrically-Heated Furnaces for the Purpose, of which the following isa specification.

My invention relates to a process and apparatus for the production ofmetals directly from their ores, and more particularly to a process forproducing cast-iron or steel of any desired degree of hardness directlyfrom iron ore without the use of solid fuel.

Heretofore ores have been reduced by heating them to the requiredtemperature by an electric current with or without the aid of gases orvapor-producing fluids introduced into the furnace; but in all furnacesof this class the electric current is short-circuited through the massof ore being treated, so that the ore forms a part of the path orcircuit of the current, and the electrodes are projected into the mass.This physical contact of the carbon electrodes with the mass of materialbeing treated renders it impossible to make iron, steel, or cast-irondirectly with a given quantity of carbon, for the reason that the metaltakes up particles of carbon from the electrodes moving from one pole tothe other, the tendency to thus take up the carbon particles dependingupon the amount of carbon contained in the metal itself and bein greatest When the metal contains theleast carbon. Again, the projection ofthe electrodes into the mass of material does not give the very hightemperature required for fusing the ores and pure metal of certainmetals of a more refractory character than iron.

A distinguishing characteristic of my invention is that I transformelectrical energy into heat by means of the voltaic are, the voltaichearth being isolated from and out of physical contact with the materialbeing treated, whereby the heat developed is utilized by radiation andconvection and not by conduction, as heretofore. aresult of this methodof applying the heat am enabled to combine with the iron the exactquantity of.

Serial No. 660,404:- (No specimens.)

carbon required for the production of castiron or steel by introducing aquantity of hydrocarbon in the form ofgas or vapor with the current ofreducing-gas supplied to the furnace.

In carrying out my invention the iron ore or the ore of any other metalthat can be reduced by hydrogen or carbonic oxidfor the process is ageneral one-is introduced in lumps of a suitable size into an electricblastfurnace without any solid fuel, but with a suitable flux or solventof an appropriate nature. Through the bottom of the apparatus, below theelectrodes and above the crucible, current of hydrogen or of carbonicoxid is introduced in a dry state, such gas being obtained from anysuitable generator. This 1 current of gas has a double functionlirst,\it reduces the ore raised by the action of the ,ivoltaic arc in thefurnace to a high temperature, and, second, as it passes over theelectrodes it carries away a great amount of heat, which it distributesin a uniformly-decreasling manner in the column or pile of ore, ,iwhichlatter thus stores and utilizes the heat. The whole heat in the interiorof the furnace is thus utilized in its entirety if the pile or column ofore has the required volume. In the particular case where cast-iron orsteel is to be produced it is necessary that car- ;bon combine with theiron. This may be atftained by introducing into the reducing-gas currentan easily-proportionable quantity of a hydrocarbon in the form of gas orvapor. When the operation of the furnace has once been regulated, theappearance of the metal and the test samples taken Will show whether itis necessary to increase or diminish the pro- ;portion of hydrocarbon. Agas or vapor con- *taining carbon in an easily-dissociable form may ofcourse be employed.

In order to obtain a metal having more or less carbon, 1 may also, as inthe Siemens- Martin process, first melt the iron and subsequentlycarburize it by adding a highly-earburized alloy obtained by my processor in other ways.

The process forming the subject of this invention thus consists inelectrically heating and melting the ore by a voltaic are isolated fromthe material being treated and in simultaneously reducing it by means ofcurrent of a suitable gas, (the air being excluded,)

and where the object in question is to produce cast-iron or steel theinvention further consistsin carburizing agentsintroducedthrough themedium of the reducing-gas current.

In carrying the process into practice I preferably use a furnace of thekind represented in the accompanying drawings, in which Figure 1 is avertical section of my improved furnace. Fig. 2 is a diagramillustrating a furnace plant complete. Fig. 3 is a horizontal section onthe line 3 3 of Fig. 1. Fig. 4: is a vertical section on the line at 4of Fig. 1. Fig. 5 represents two sections on different planes, theright-hand half of the figure being a section on the line 5 5 and theleft half a section on the line 6 6 of Fig. 4. Fig. 6 is a horizontalsection of a modification. Fig. 7 is a vertical section on the line 7 7of Fig. 6, and Fig. Sis a horizontal section of another modification.

The electric furnace or electric blast-furnace, which I preferablyconstruct in a cylindrical form, is composed of three principal partssuperposed and independent of one another as far as the mounting andconstruction are concerned-namely, the receiver portion a, the electricmelting-chamber Z), and the crucible c. The crucible is not, however,essential, and the furnace could be worked without the same. Each ofthese three parts, generally speaking, forms a chamber the walls ofwhich are made of a refractory substance and covered, if necessary, witha sheet-metal or suitable jacket or mantle. As I have stated, thereceiver a and the melting-chamber h are independent of the crucible cand can be successively dismounted for repairing or other purposes. Thefurnace may be supported on a suitable base in a frame or casing carriedby columns. The receiver a is provided with the usual charging apparatusa and with a gas-outlet a Into the melting, heating, or working chamberZ) enter the electrodes Z). The arrangement, however, of the electrodesor of the voltaic are or arcs constituting the heating means may varyaccording as a chamber of large heating-surface or a small chamber ofintense heating capacity is required. The electrodes Z) may be protectedby means of a deflector or shield W, of a refractory material. Thisshield or shields prevent the ore from coming into contact with theelectrodes. Their shape may vary. In case of a chamber having a singleare it will be sufficient to provide an angular piece covering theelectrodes from one point of the furnace to the point diametricallyopposite. In the case of a circular intenselydieated chamber (in whichthe electrodes are arranged like Jablochkoff candles) the roof may bevault-shaped and be arranged in line with the axis of the, furnace andbe provided with shields connecting the said vault to the sides orwalling and covering at the same time the electrodes, while stillleaving sufficientlymxide spaces for the passage of the ore.

In Figs. 6, 7, and 8 I have shown two different forms of protector orshield for the electrodes. In Figs. (3 and 7 the protecting-shieldconsists of a ring or circular plate f, secured to the walls of thefurnace by radial arms g. The platefis formed with a central opening itand is bent downwardly to form an annular flange 2', which depends overthe ends of the electrodes 1). In Fig. 8 the shield consists of a flatimperforate plate j, secured to the furnace-walls by radial supportingplates or arms 7;, which extend over the electrodes and leave spaces Zfor the passage of the metal.

It is obvious that any form of shield which will prevent contact of theelectrodes with the metal will serve the purpose, and my invention isnot restricted to any specific form of shield or protectingplate for theelectrodes.

The crucible 0 below the fusion-chamber is provided with a cast oroutflow opening 0. A passage 0 communicating with the cham her 0 bypassages 0 and consequently with the melting-chamber b and the receivera, serves to convey the current of reducing and carbureting gas into thefurnace. The inlet of this passage is in communication through c with agas-generator d, Fig. 2, which supplies the furnace with reducing andcarbureting gas.

The operation of the furnace will be readily understood. If we supposethe apparatus to be in action-the ore being, for example, sup-- pliedautomatically, the electric current traversing the electrodes, and thecurrent of reducing (and, as the case may be, carburizing) gas beingregularly supplied from the gasgenerator-we shall find that inproportion as the ore descends in the receiver and ap proaches the arcchamber its temperature rises, and the reduction of the ore graduallytakes place down to the fusion-zone b". The free metal (carburized, ifrequired) flows through the orifice Z)" into the crucible or chamber 0,where it accumulates and whence it is discharged through the cast oroutflow opening 0. The gases resulting from the reduction escape fromthe furnace through the orifice a It is evident that without departingfrom the principle on which this furnace is constructed I may yet inpractice employ constructional forms and arrangements which greatlydiffer from those described in the body of this specification, withreference to the accompanying drawings, accordingto the particular caseand to the special method of carrying my process into practice.

The furnace may or may not be provided with cooling means, such as watercirculation around the parts liable to be overheated, as illustrated atm in Fig. 4-.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is- 1. The process of obtaining metal direct from the oreconsistingin subjecting thelower Ito end of a descending column of oreto a high temperature by a Voltaic are not in physical contact with theore, and simultaneously causing a current of heated reducing-gas to flowupwardly through the column of ore.sub stantially as set forth.

2. The process herein described of obtaining metal direct from the ore,which consists in subjecting the ore to a high temperature solely byradiation and convection from a voltaic arc, and simultaneously causinga cur rent of reducing-gas containing a carburizing agent to flowthrough the ore, whereby ap proximately the exact amount of carbon desired may be combined with the iron.

Witnesses:

J OHN MILES, v EDWARD I. MAOLEAN.

